Green, who has four other "wives" and 30 children in all, including seven with Kunz, already is serving five years for bigamy and other charges. He was convicted last year in Utah's biggest polygamy case in five decades.
In the child-rape case, prosecutors submitted Kunz's testimony from previous hearings, as well as her 1973 birth certificate and the 1986 birth certificate of the couple's first child. "Basically, this case comes down to math," the judge said. "We know a normal human gestation takes nine months."
Kunz refused to testify; spouses do not have to take the stand against each other. "We don't feel like this was a crime," she said after the verdict.
The judge had previously rejected defense arguments that the statute of limitations had run out. The defense had also argued that the case should be thrown out because the alleged rape did not take place in Utah but in Mexico, but the judge agreed with prosecutors that Green hatched a conspiracy in Utah to marry the girl.
At the time, someone as young as 14 could legally marry in Utah. That has since been raised to 16. The Mormon Church renounced polygamy in the 1890s as part of the agreement that led to Utah statehood. But it continues to be practiced by an estimated 30,000 in Utah and elsewhere in the West.
Green practically dared prosecutors to go after him by appearing on TV talk shows such as Sally Jessy Raphael's to talk about his many wives.